Overall objectives of total project: a. To document the development, maturation, distribution and incidence of MVCs in the colon of mice. (MVC equals Multivesicular Cell). b. To determine if MCVs, or cells with similar characteristics, are also present in any significant number in the stomach and small intestine of mice. c. Should MVCs or comparable cells be especially numerous in any particular region of the stomach and small intestine, then embryological studies will be carried out on these areas as well. Goals for the current year: a. Using light microscopy an attempt will be made to determine if MVCs are especially numerous in any particular region of the gut. b. Electron microscopy will be used to determine the development and maturation of MVCs.